1. Field
The exemplary embodiments generally relate to material handling systems and, more particularly, to transport and storage of items within the material handling system.
2. Brief Description of Related Developments
Multilevel storage and retrieval systems may be used in warehouses for the storage and retrieval of goods. Generally the transportation of goods into and out of the storage structure is done with lifts for transfer to a vehicle on a storage level, vehicles travelling up ramps to a predetermined storage level, or with vehicles that include lifts traveling along guide ways. Goods stored within the storage and retrieval system are generally stored in storage spaces on each storage level such that a transport vehicle disposed on that level has access to one level of storage spaces. Generally, the lifts that transfer items to and from the storage spaces carry the vehicles between different storage levels, are incorporated into the vehicles (such as with a gantry crane) or have a paternoster configuration where the lift payload shelves continually circulate around a frame at a predetermined rate.
The case units output from the multilevel storage and retrieval systems are transferred to a packing station where the case units are placed on pallets for shipping. Generally the pallets include case units of similar size and shape so that stable case levels, sometimes with paperboard sheets disposed between the levels, are formed on the pallets. In some instances each level of tier of the pallet is separately formed and then placed on the pallet to form stacked tiers. Mixed pallets are also possible. Generally when forming a pallet layer cases are placed in a buffer station or other location at the palletizing station so that the dimensions of the case are measured. A computer or other processor determines an arrangement of the cases based on the dimensions and instructs a robot to pick the cases for placement in the pallet layer.
It would be advantageous to sort case units for placement on a pallet during transport of the case units out of the storage and retrieval system storage structure to increase throughput of the storage and retrieval system.